DD218726A5 - FARBWIEDERGABEGERAET - Google Patents

Abstract

CIRCUIT ARRANGEMENT FOR A 16-KZ TRANSMISSION TRANSMISSION DEVICE BY PLL, WHICH IS USED FOR THE USE WHERE IT ARISES TO TRANSFER PAYMENT EVEN THROUGH THE EXISTING OF A TELEPHONE CONNECTION THROUGH DIRTY-BAND CONNECTING ROUTES. THE OBJECT AND OBJECT OF THE INVENTION IS TO OBTAIN A CIRCUIT ARRANGEMENT WHICH REQUIRES LESS WORK EXPERIENCE ALREADY KNOWN, A MINIMUM OF ELEMENTS AND A MORE REDUCED ROOM NEEDED, WHICH HAS A REDUCED SENSITIVITY OF 16KHZ RECEPTION AND THE BOTH FOR BOTH IMPLEMENTATION MEASURES REQUIRED TWO DIFFERENT CIRCUITS SHOULD BE REDUCED TO A CIRCUIT, WHICH MAY CHANGE THE IMPLEMENTATION DIRECTIONS WITH LESS LENGTH. THE TASK IS MADE THEREFORE BY GIVING AN INTEGRATED PHASE CONTROL TO THE OPERATION WHERE THE TEMPERATURE COEFFICIENT THROUGH THE CIRCUIT IS COMPENSATED BY AN R-C COMBINATION.

Description

Berlin, May 25, 1984 63 789/13

Color reproduction device

Field of application of the invention

The invention relates to a color display device with color display tubes including a penetration cathodoluminescent screen and a power supply for switching the post-acceleration (PDA) voltage between different values to produce the desired color.

Characteristic of the known technical solutions

Penetration screens are known and described in a publication "Performance of Penetration Color CRTs in Single-Anode and Dual-Anode Configurations" by GR Spencer in Proceedings of the SID ₁ Vol. 22/1, 1981, pp. 15-17 , GR Spencer highlights some problems with the use of penetration goggles in single-anode CRTs. As is known, using a dual primary color penetration phosphor, different colors are produced by varying the anode screen voltages of the tube. A dashed line in Fig. 3 of the Spencer publication shown effects is that change the spot size and thus the line width in the usable voltage range. Consistent with this, the electron beam is to be refocused if the spot size is to remain constant. Another problem with anode screen voltages is that in order to maintain a substantially constant image size, the deflection current must be varied with the screen voltage. GR Spencer proposes that

To reduce the effects of these problems by separating the anode of the electron beam generator and the transparent electrode on the luminescent screen into two independent electrodes. However, this double electrode arrangement causes an enlargement of the line width with magnifying beam current and requires a larger deflection current with a larger screen voltage.

One proposal for separating the addressing of an electron beam from the light and color generation in a display tube-having a penetration phosphor screen is disclosed in GB-PS 8230244 (PHB 32924). In this patent, a single-jet reproducing tube with a channel plate electron is described every few times, which contains a stack of hole dynodes whose cavities are aligned to form channels. A low energy electron beam is scanned at the input surface of the electron multiplier. The electron multiplier generates a current-multiplied electron beam which serves for the generation of light and color. The cathodoluminescent luminescent screen contains groups of phosphor elements, wherein at least one luminescent element of each group has a penetration component with two color phosphors, e.g. As red and green, and another phosphor element, for. B. Blue contains.

another solution for producing color images with a display tube having a channel multiplier and a penetration cathodoluminescent luminescent screen is described in GB-PS 1402547 (PHB 32 193). In this patent specification, a continuous two-layer red-green penetration phosphor layer is provided on the front panel or another, optically transparent carrier substrate is arranged between the output surface of the electron multiplier and the front panel. In addition, a blue-luminescent phosphor is on

a second color selector electrode is mounted on the output surface of the electron multiplier, and a second color selector electrode is mounted between the green penetrating phosphor and the faceplate or its supporting substrate, the red penetrating phosphor being closer to the electron multiplier than the green one. In operation, by varying the field structure between the first and second color selector electrodes, one of the various phosphors may be activated by the electron beam exiting the channel multiplier.

When scanning such screens, it is necessary to rapidly switch the post-acceleration voltage applied to the screen electrode, which is coextensive with the cathodoluminescence screen, between a low voltage of about +7 kV with respect to the output of the channel multiplier and a high voltage of about +14 kV, because otherwise the color purity of the image is adversely affected.

Known high-voltage circuits often contain a low-voltage source, which by means of a transformer and a rectifier arrangement or a voltage multiplier, for. Cockroft-Walton type, for example, is formed to a high voltage. In general, a capacitor is connected between the output of the high voltage circuit and a reference voltage point, ζ, B. earth. In operation, the voltage at the output terminal can be increased rapidly, but the reverse is not always the case due to the time required to reduce the capacitor charge to the desired level. This problem is generally solved by a discharge process on the capacitor by means of suitable switching means, eg, a hot cathode tube or a series circuit of high voltage transistors. In both cases, the additional circuitry is extensive.

rich and / or expensive, particularly when used with a flat display tube of the type described in G8-PS 2101396 (PHB 32,794) having a screen size on the order of 100 mm diagonally and with a high resolution glass-matrix electron multiplier.

Aim of the invention

Zie.l the invention is to avoid the aforementioned disadvantages of the prior art.

Explanation of the essence of the invention - '

The object of the invention is to reduce the dimensions and costs of the power supply to be used with a display tube in which a channel multiplier and a penetration lighthouse are provided »

This object is achieved with a reproducing apparatus according to the invention comprising a color display tube with an outer bulb in which an electron gun is provided, a channel multiplier with entrance and exit surfaces, scanning means for scanning the electron beam at the entrance surface and a cathodoluminescent screen parallel thereto Distance from the exit surface of the electron multiplier is constructed, is achieved in that the Kathodolumineszenzschirm contains at least a two-color penetration phosphor and an adjacent electrode and a power supply for supplying predetermined potential differences between the exit surface of the multiplier and the electrode, wherein the power supply a Glühkathodenröhre in AuSenkolben to simplify fast switching operations, the potential difference between at least two voltages contains *

In one embodiment of the display device, in the hot cathode tube, an external anode resistor is connected in series with the power supply, which produces a substantially constant voltage during operation and in which the hot cathode tube is activated to switch the potential difference between at least two voltages.

In another embodiment, the power supply is controlled to generate at least two predetermined voltages and the hot cathode tube is energized to provide a substantially instantaneous change between a higher voltage and a lower voltage.

The device according to the invention makes it possible to achieve the penetration principle of color selection by simply switching the screen voltage without the need for corrections in the scanning amplitude or in the beam system focus in conventional penetration-type reproduction tubes without channel multipliers. In addition, if there is the possibility to switch the screen voltage quickly, the color purity of the image is guaranteed. The arrangement of the thermionic tube in the tube piston, the additional volume in relation to the volume of the display tube is negligibly small and the cost is low. The hot cathode tube may include a triode or tetrode, the anode of which is connected via a low impedance path to the shield electrode of the display tube.

Other external connections can be avoided by connecting the tube cathode via a low-impedance path to the cathode of the beam system of the display and that the heating filaments can be connected in parallel with indirectly heated cathodes.

There is only one external connection to the grid of the triode or to the first (or control) grid of the tetrode. Since the signal to the grid or to the first grid is a switching control voltage of about 10V, this further external connection may include an additional pin in the normal terminal in display tubes.

The video control for the display tube can be better placed on the grating of the beam generating system than on the cathode, as is common in a conventional color display tube for television and Datagraphische playback. In a flat display tube of the type described in GB-PS 2101396, in which folded electron optics and electrostatic image deflection are provided, it is important to keep the beam energy constant, otherwise the electron beam path will change and distort the reproduced image would. This problem is avoided by the connection of the video controller to the grating of the beam generating system. .

The anode of the hot cathode tube may advantageously include an extension of the shield electrode, whereby the volume of the tube is further reduced.

A feedback connection can be provided between the shield electrode and the power supply, wherein the shield voltage is kept substantially constant despite the variations in the shield current. As a result, unwanted color changes can be avoided, especially with a bright image.

The channel multiplier may be of the glass matrix type, particularly suited for small, high resolution, datagraphic display tubes, or may contain a stack of separate metal dynodes which are better for larger ones

ii reproduction tubes are suitable

embodiment

Some embodiments of the invention are explained below with reference to the drawing. Show it :

1 shows a circuit diagram of a first embodiment of the invention with a magnetically deflected display tube and a triode tube,

2 shows a circuit diagram of a second embodiment of the invention with a flat, electrostatically deflected display tube and a tetrode tube, and

Fig. 3: a circuit diagram of a third embodiment of the invention, in which the display tube is the same as the tube shown in Fig. 1.

In the drawing, the same figurines are used for the same elements.

In Fig. 1, the reproducing apparatus with a display tube, 10 and a high voltage power supply 12 is shown.

The display tube 10 includes a metal or glass bulb 20 having an optically transparent faceplate 22. The faceplate may be curved or flat. In the piston 20 is provided a beam generating system 24 for generating a low voltage, low current electron beam. The beam generating system 24 includes a cathode 28_, a control grid 30 to which a video control signal is applied, and two anodes 32 and 34 for focusing the electron beam 26. An electromagnetic beam deflector 36 is provided in the piston 20.

The output voltage from the electron multiplier 38 is applied to a Ka'thodolumineszenzschirm 40 mounted parallel to the electron multiplier 30, When the front panel 22 is flat and parallel to the exit surface of the electron multiplier 38, Alternatively, the screen may be mounted on an optically clear, flat support mounted parallel to the exit face of the electron multiplier 38. The screen 40 contains a penetration phosphor layer. The penetration layer can be a green phosphor layer on an optically transparent support, such. B, the front panel 22, a non-luminous material barrier layer, a thin red phosphor layer on the barrier layer, and an aluminum film covering the red phosphor. With the aluminum layer, an electrical connection is produced, via which a Nachbeschleunigungsspannung is supplied. For the sake of clarity, the aluminum layer is referred to as the shield electrode 42. Another known method for producing the penetration layer is called onion-shell phosphor technology, in which green phosphor particles, which are covered by a barrier layer and are themselves covered by red phosphor grains, are deposited on a transparent support. In operation, the red phosphor is activated by a low excitation voltage and the green phosphor by a high excitation voltage.

The electron multiplier 38 may include a stack of metal dynodes or a glass matrix stack. In the first case, the electron multiplier 38 contains a stack of discrete dynodes isolated from each other. Apart from the

Input dynode with convergent openings have the remaining dynodes barrel-shaped openings. If the dynodes are made of a material that is not highly secondary, a layer of secondary particulate material may be placed in the openings. In operation, each dynode is maintained at a voltage higher than the preceding dynode in the stack in the range of 200 ... 500V. The details of the design, construction, and detailed operation of the current multiplier 38 are not materially important to a good understanding of the invention, but if desired, for example, reference may be made to FIGS

GB-PS 1434053 (PHB 32 324) and GB-PS 2023332A (PHB 32 626). The details of which are to be considered as included in this description.

For a glass matrix channel multiplier 38, this contains thousands of channels 12 microns in diameter and 15 yards in pitch. The preparation of glass matrix channel multipliers is well known and will not be discussed further here. However, reference may be made to Acta Elektronica, Volume 14, No. 2, April 1971 for further information.

The high voltage power supply 12 includes an oscillator 50 whose output is connected to the primary winding of a high voltage transformer 52. The output of the oscillator 50 is substantially constant. The secondary winding of the transformer 52 is connected to the screen electrode 42 via a rectifier 54 and a series resistor 56. A smoothing capacitor 58 is connected between the output of the rectifier 54 and a voltage reference point, e.g. B. ground, connected. The node of the rectifier 54 and the capacitor 58 is connected via a resistor 56 to the shield electrode 42, which is also the anode resistance.

stand for a hot cathode tube 70 is, which is used for switching the screen voltage between a high and a low value, and vice versa. ·

In FIG. 1, the thermionic tube includes a triode having an anode 72, a grid 74, and a cathode 76. The tube 70 is equipped with a bulb 20. Since the anode 72 and the electrode 42 carry the same potential, the anode 72 may advantageously include an extension of the shield electrode 42, whereby a separate connection to the anode 72 through the wall of the piston 20 can be avoided. The cathode 76 carries the same voltage as the cathode 28 of the radiation generating system and the entrance side of the channel multiplier 38, so that they can be connected to each other via low-impedance paths. A separate connection to the grid 74 must be provided. By applying an appropriate switching voltage to the grid 74, the tube 70 is switched every 10 ms between two conducting states such that the screen voltage is held at the required rules Pe. ¹

Since it is desirable to maintain the screen voltage constant despite changes in the screen current due to changes in brightness and picture content, feedback is provided between the anode 72 and the grid 74. This is done by connecting the output of an operational amplifier 78 to the grid 74. The switching signal 80 is applied to an inverting input of the operational amplifier 78 and a divisional part of the screen / anode voltage goes to the non-inverting input of the operational amplifier 78. Potential distributor with a feedback resistor 82 and another resistor 84 obtained.

In Fig. 2 an embodiment of a flat display tube 10 with folded electron optics is shown. An embodiment of such a flat display tube 10 is described in detail in GB-PS 2107396A, which description is considered to be incorporated herein by reference. Oedoch in focus produces the beam generating system 24 has a low current _f low voltage electron beam 26. It undergoes line scanning using a pair of dispersion plates 85 before the rotation over 80 ° in a Urakehrlinse 86. By means of a series of substantially parallel extending electrode 88, the electric field between the electrodes 88 and the input to the channel multiplier .38 for making vertical scans across the input of the channel multiplier 38. The current multiplied beam from the channel multiplier 38 is accelerated to the screen 40 by the field established between the output of the channel multiplier 38 and the shield electrode 42. The channel multiplier 38 may be in the form of a glass matrix or a separate metal dynode.

The maximum voltage supply 12 will now be explained in more detail below with reference to FIG. 1. ,

However, the hot cathode tube 70 in the tube piston 20 contains a tetrode whose second grid 90 is connected to the input of the channel multiplier 38, which itself is connected to a reference potential source, i. H. with Hasse, is connected. The arrangement of the second grid 90 reduces the grid control voltage of the tube 70. The cathodes 28 and 76 are interconnected and reconnected to a -400 V source. Since cathodes 28, 28, and 76 are indirectly heated because, as illustrated, their heating elements 92 and 94 are connected in parallel. The video control for the

Play raw re 10. reaches the grid 30 of the beam generating system. In this electrostatic beam deflection embodiment, it is extremely important to keep the beam energy constant, which would not be possible if the video control is applied to the cathode 28. If the beam current is varied, the reflection of the beam at the return lens 86 would vary, and at the image deflection stage, rather than recording a straight line, the line would be distorted with the variation in beam energy. The cathode 76 and the first and second grids 74 and 90 may advantageously include a cathode, a grid, and a first anode of a conventional beam generating system. ·: .-,

The power supply arrangement for the embodiment of Fig. 3 differs from the embodiments of Figs. 1 and 2, in which the output voltage of the oscillator 50 is constant and the switching operation of the screen voltage from the hot cathode tube 70 is performed. However, in Fig. The oscillator output voltage by means _; of the operational amplifier 78 is supplied to the input 60 of the oscillator 50. The node of the rectifier 54 and the capacitor 58 is. directly to the shield electrode 42 and to the anode 72 of the tube 70. A pulse source 98 is connected to the triode 70 triode. The cathodes 28 and 76 of the beam generating system 24 and the tube 70 are grounded. The feedback to the oscillator 50 from the output of the high voltage power supply 12 is supplied by the operational amplifier 78. .

In operation, the charge of the capacitor 58 varies in accordance with the switching signal 80. The transition from low to high voltage is essentially instantaneous, with

the color purity is ensured in the entire area of the screen 40. However, the transition from a high to a low voltage, when the charge of the capacitor 58 is not substantially instantaneously reduced, becomes a slower transition due to the exponential decay of the charge of a capacitor 58. Effect of such a decay process is that the color purity of the image changes over the image, z. For example, at the beginning it is predominantly green and changes more and more to red. In Fig. 3, the rapid reduction in charge of the capacitor 58 is accomplished by connecting the tube 70 by means of the pulse source 98. Depending on the nature of the scan, the pulse source 98 generates a pulse at the point where the power supply 12 is high switched to the low voltage state and raster scan this could be done either in a line return or a picture return.

In these embodiments, a reproducing apparatus is provided which can produce a color image whose resolution depends on both the pitch of the channels in the electron multiplier and the spot size of the beam generating system. In a glass matrix multiplier with a typical channel line of 15 yards, the resolution is in most cases determined by the spot size of the electron beam.

It will be appreciated that the illustrated embodiments are not mutually exclusive in the sense that in Fig. 2, a triode tube and in Figs. 1 and 3, a tetrode are used. Further, to simplify the description, it has been assumed that the screen is completely a penetration screen, but element groups of the type shown in FIG

-Ia-

In British Patent Application 8230244 (PHB 32924), wherein: in each group one element type is a two-color penetration phosphor and a second element type is a phosphor element of a third color. However, it should be noted that the electron multiplier described in application 8230244 is one of the metal dynode type.

Claims (13)

Claim of invention . Reproducing apparatus having a color display tube with an outer bulb in which a 3trahlerzeugungssystem for generating an electron beam, a channel multiplier with entrance and exit surfaces, means are provided for scanning the electron beam over the entrance surface and a parallel cathodoluminescent screen which is at a distance of the output surface of the electron multiplier, characterized in that the Kathodolumineszenzschirm contains at least a two-color penetration phosphor and an adjacent electrode and a power supply for supplying predetermined Pötentialunterschiede between the exit surface of the electron multiplier and the electrode, which power supply a Glühkathodenröhre in the outer bulb to facilitate the rapid switching operations the potential difference between at least two voltages. 2. The reproducing apparatus of item 1, characterized in that the thermionic tube is connected in series with the power supply with its external anode resistor / generates a substantially constant voltage during operation, and that the thermionic cathode tube is activated to switch the potential difference between at least two voltages. . 3. A reproducing apparatus according to item 1, characterized by controlling the power supply to generate at least two different predetermined voltages, and activating the hot cathode tube to provide a substantially instantaneous change between a higher and a lower voltage. 4. A display device according to items 1, 2 or 3, characterized in that the hot cathode tube is a triode having a cathode, a grid and an anode, which via a low-impedance path with the shield electrode , _ - \ is connected, wherein a switching control voltage is applied to the grid in operation, 5. A reproducing apparatus according to items 1, 2, or 3, characterized in that the Glühkathodenröhre is a tetrode having a cathode, a first and a second grid and an anode which is connected via a Niederimpedahzweg with the shield electrode, wherein a switching control voltage is placed in operation on the first grid and the second grid leads the potential of the entrance surface of the electron multiplier » 6. A reproducing apparatus according to item 4 or 5, characterized in that the anode of the hot cathode tube is an extension of the shield electrode. 7 »reproducing apparatus according to items 4, 5 or 6, characterized in that the cathode of the Glühkathodenröhre is connected via a low impedance path to the cathode of the electron beam generating system and the video control for the beam generating system is fed to a grid of the beam generating system. 8th.' A reproducing apparatus according to any one of items 1 to 7, characterized in that a feedback terminal is provided between the screen electrode and the power supply, wherein, in spite of fluctuations in the screen current, the screen voltage is kept substantially constant. .r ' 9. A player according to any one of items 1 to 8, characterized in that the channel multiplier contains a stack of separate metal dynodes. 10. A playback device according to one of the items 1 to 8, characterized in that the channel multiplier contains a glass matrix » 11. A display device according to any one of items 1 to 10, characterized in that the outer bulb is flat and contains a folded electron optics. 12. reproducing apparatus having a structure and an arrangement for operating substantially as described with reference to FIGS. 1 and 2 of the drawing. 13. »Viede rgabege advises with a structure and an arrangement for operation substantially as described with reference to FIG. 3 of the drawing. For this 2 pages drawings.